The Scienova Company already offers various dialysators as inserts with laterally attached semi permeable membranes for vertical use in standard deep well micro plates and centrifuge tubes (c.f.http://www.scienova.com/xanario/xpressmicrodialyzer100-c-80-2.html). They are characterized by quick dialysis of small volumes in dialysis capillaries. Sample introduction and retrieval of the sample volumes is performed in an upper portion of the dialysators with standard liquid handling technology. This, however, has the disadvantage that mixing in the sample cavity by dispensing is hardly practicable. The sample volume is limited by the capillary geometry that is being used for dialysis. When the capillary cross section and the capillary length increase to increase volume sample retrieval becomes more difficult since the liquid column is interrupted and air bubbles move in. When the sample volume shall be significantly increased in spite of very limited space when using vessels according to the SBS standard a new solution has to be found.
When the dialysators are used as inserts the sample and the solution that is disposed in the outer vessel for example a dialysis buffer cannot be mixed, removed or exchanged anymore with pipettes or other liquid handling technology. The solution that is disposed in the outer vessel can only be changed after removing the insert. This solution is described under DE10 2007 011 866 A1, WO 002008106960 A1, US 020100136596 A1, EP 2 129 464 A1.
The Thermo Scientific Company sells a device which includes 48 individual inserts for vertical dialyzing in the micro titer plate format (c.f. herein for example www.piercenet.com/product/rapid-equilibrium-dialysis-red). These inserts are made from a plastic base element with a tube made from a dialysis membrane forming the sample cavity. The inserts are arranged in a grid of micro plates. The inserts, however, are adapted with respect to their geometry to a special outer plate for the inserts. This does not facilitate using standard vessels like deep well plates. The handling complexity is relatively high since the inserts are used individually and the special outer plate has to be dismounted and cleaned after use. Filling and emptying is performed in that pipette tips have to be run to the bottom. In particular during manual operation there is a risk that the pipette tip can damage the semi permeable membrane. The large free opening increases the contamination risk. The solution is described in WO 002006055756 A3, U.S. Pat. Nos. 7,604,739 B2, 8,034,242 B2, US 020060102547 A1, US 020100264085 A1, EP 1 827 659 A2, EP 1 827 659 A4.